In industries that have the potential to contaminate the environment, such as oil wells, gas wells, induced hydraulic fracturing sites, storage sites, mining operations, and the like, it is often desirous to provide a means to protect the environment from contamination, and reduce the cost and complexity of spill cleanup. At drilling sites, many potential contaminating fluids are used. Depending on the type of drilling being performed, various fluids can include drilling mud, fuels, fracturing chemicals, corrosives and flowback water. Spills of any of these liquids must be cleaned from the environment. If the soil at the drill site is contaminated, the contaminated soil must be remediated. To reduce the amount of contaminated soil and water and to eliminate regulatory fines, many operating companies excavate the site, cover it with stone or crushed rock, place a geotextile over the crushed rock, and then loosely place a geomembrane over the surface. A geotextile is typically a strong synthetic fabric used in civil engineering that stabilizes loose soil. Geotextiles are permeable fabrics which generally come in three basic forms: woven, needle punched, or heat bonded. The geotextile protects the geomembrane from sharp edges in the stone or crushed rock base. The geomembrane is non-permeable and contains the leaks and spills for subsequent removal, e.g., until an on-site vacuum truck can remove them without impact to the environment.
There are issues with this type of containment barrier. Traditional HDPE geomembranes for ponds and pits were not designed for foot and vehicle traffic. HPDE geomembranes are prone to punctures, e.g., from dropped hoses, vehicles and equipment movement. The geomembranes are also extremely slippery to work on, even with a textured surface. Friction treatment of geomembrane or geotextile surfaces to prevent slippage is disclosed in U.S. Pat. Nos. 5,056,960 and 5,137,393, respectively. To increase traction in standing water, snow and ice, some operating companies place, but do not bond, an additional layer of a geotextile over the HDPE geomembrane to reduce slip hazards. However, in this application, the geotextile slides on the geomembrane, producing a slip hazard and additionally, the geotextile is subject to wrinkling, bunching up or folding to produce trip hazards. The loose material can also be pulled into vacuum hoses while removing liquids from the surface. The loose geotextile can mask punctures in the geomembrane beneath it, which may only be discovered after a spill or leak.
A polymer sheet that has geotextiles affixed by mechanical engagement on both sides is disclosed in U.S. Pat. Pub. 2012/0219746. This structure affixes the layers by embedding a portion of the geomembrane into the geotextile to prevent separation. While this prevents movement between the layers, repairing damage in the containment liner can be difficult since the layers cannot be separated. The entire damaged portion must be replaced. Additionally, while the top layer of geotextile will protect the geomembrane from punctures and the like, the flexibility of the geotextile is greater than the geomembrane. Thus, when heavy vehicles or objects are moved across the surface and have a change in direction, shear forces on the liner can cause a tear in the geomembrane or can cause a tear in the geomembrane and the geotextile. This tear will prevent proper containment, is difficult to repair and may go unnoticed if the geotextile is not damaged.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
An object of the present invention is to provide a ground cover for use as a containment barrier that will allow both foot and vehicle traffic.